The present invention relates to an exciting device for an electromagnetic connection device in which the extraction end of an exciting coil and an external connecting terminal are connected outside a yoke.
Conventionally, an electromagnetic connection device such as an electromagnetic clutch or an electromagnetic brake includes a yoke to guide the magnetic flux of an exciting coil to an armature side. The yoke is formed into a ring shape so as to pass a rotating shaft to the axis. The yoke has an annular groove open to the armature side. The exciting coil is stored in the annular groove. The exciting coil includes two extraction ends that are a winding start end and a winding termination end. These extraction ends are derived out of the yoke through the bottom wall of the yoke, which serves as the bottom of the annular groove, and connected to a power supply connector fixed to the yoke.
Exciting devices of this type for an electromagnetic connection device are disclosed in Japanese Utility Model Publication No. 63-6512 (literature 1) and Japanese Utility Model Laid-Open No. 2-59327 (literature 2).
The exciting device disclosed in literature 1 includes a power supply connector with a structure in which a pair of terminals are buried in a terminal housing. This connector is attached to a fixing member provided on the bottom wall of a yoke. The pair of connectors each include a plate-shaped locking portion bent to extend to the opposite side of the yoke. In this exciting device, two extraction ends of an exciting coil are derived out of the yoke through a rubber bushing provided on the bottom wall of the yoke, clamped by the above-described plate-shaped locking portions, and in this state, connected to the plate-shaped locking portions by a fixing means such as soldering or fusing (heat caulking). The connected portions are covered by a lid and cut off from the outside. Fixing of the connector is done by passing a plurality of fixing pawls formed by cut-and-raising through the above-described lid and expanding the distal ends of the fixing pawls to press the lid against the terminal housing.
The power supply connector disclosed in patent literature 2 is formed by a terminal housing and a pair of terminals. The terminal housing includes a convex portion fitted in a first through hole formed in the bottom wall of a yoke. Two second through holes are formed in the convex portion to pass the two extraction ends of an exciting coil. The pair of connectors each include a locking portion extending to the opposite side of the yoke. The locking portions are provided at positions adjacent to the above-described convex portion. The extraction ends derived from the second through holes are bent and hooked on the locking portions, and soldered in this state. Fixing of the connector is done by pressing the terminal housing against a fixing plate provided on the yoke using the fixing pawls of the fixing plate.
As described above, in the exciting device disclosed in literature 1 or 2, the extraction ends of the exciting coil need to be clamped by or bent and hooked on the locking portions of the external connecting terminal and thus temporarily fixed. Hence, the electromagnetic connection device including the exciting device needs an assembly process for temporarily fixing the extraction ends, resulting in low productivity.